2017-12937. Special Conditions: SNECMA, Silvercrest-2 SC-2D; Rated 10-Minute One Engine Inoperative Takeoff Thrust at High Ambient Temperature; Withdrawal

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Final special conditions; withdrawal.

SUMMARY:

The FAA is withdrawing previously published special conditions for the Silvercrest-2 SC-2D engine model. We are requesting the withdrawal because the “Rated 10-Minute One Engine Inoperative Takeoff Thrust at High Ambient Temperature (Rated 10-Minute OEI TOTHAT) is not needed.

DATES:

As of June 27, 2017, the special conditions published on October 31, 2014, at 79 FR 64666, are withdrawn.

FOR FURTHER INFORMATION CONTACT:

Tara Fitzgerald, ANE-112, Engine and Propeller Directorate, Aircraft Certification Service, 1200 District Avenue, Burlington, Massachusetts, 01803-5213; telephone [phone]; facsimile [phone]; email [e-mail].

SUPPLEMENTARY INFORMATION:

Background

On April 19, 2011, SNECMA, now known as Safran Aircraft Engines (SAE) applied for a new type certificate for the Silvercrest-2 SC-2D engine model. At that time, the Silvercrest-2 SC-2D engine model was to have a novel or unusual design feature when compared to the state of technology described in the airworthiness standards for aircraft engines. The design feature included an additional takeoff rating for the Silvercrest-2 SC-2D engine model, named “Rated 10-Minute One Engine Inoperative Takeoff Thrust at High Ambient Temperature” (Rated 10-Minute OEI TOTHAT). It was intended to maintain the takeoff thrust in certain high ambient temperature conditions for a maximum of 10 minutes with one engine inoperative (OEI).

Reason for Withdrawal

The FAA is withdrawing Notice No. 33-014-01-SC because of concerns raised over the sufficiency of the “Rated 10-Minute OEI TOTHAT” special condition to meet the Automatic Takeoff Thrust Control System (ATTCS) design requirement specified in Title 14, Code of Federal Regulations (14 CFR) part 25, section I25.5(b)(2).

The proposed takeoff rating was for use during OEI events that occur during takeoff in high ambient temperature conditions, up to 5 degrees Celsius hotter than the rated takeoff corner point. The assumptions for this rating are no longer valid and the “Rated 10-Minute OEI TOTHAT” is not needed.

Conclusion

This withdrawal does not preclude the FAA from issuing another notice on the subject matter in the future or committing the agency to any future course of action.

Issued in Burlington, Massachusetts, on June 13, 2017.

Carlos A. Pestana,

Acting Assistant Manager, Engine and Propeller Directorate, Aircraft Certification Service.